Reporting Standards for Percutaneous Interventions in Dialysis Access

New therapeutic options provided by off-label deployment of stent graft for tailored arteriovenous access salvage: Two cases

A tailored therapy to patient requirements by combining endovascular and surgical steps can be necessary to prolong the life of a vascular access. Stent grafts play a growing role for the therapy of dialytic access complications. Randomized multi-center trials, however, support the on-label use of stent grafts in the treatment of graft venous outflow and in-stent restenosis. The main contraindication to their use is an ongoing infection. We report two cases of new off-label application of Viabahn (Gore, flagstaff, USA) stent graft. In the first case, the failure of a radiocephalic early cannulation graft was treated by stent graft placement on the arterial inflow anastomosis, when emergent angiographic examination revealed the previously unknown high takeoff of the radial artery from the axillary artery. At 13-month follow-up, the target lesion remained untreated. In the second case, elbow stent graft occlusion with extended thrombosis occurred in a right radiocephalic fistula after 3 years of unassisted patency. Being the last option for vascular access, successful endovascular recanalization was carried out. After 3 months, however, the clinical setting relapsed. A two-stage hybrid strategy with vascular surgeon was arranged due to ongoing signs of local infection. Flow was restored by emergent thromboaspiration associated with a new stent graft placement as a endovascular bridge to subsequent surgical treatment. After 2 days, the overlapped stent grafts were excised as planned. Surgical rerouting was completed by polytetrafluoroethylene prosthetic bridge implantation across the elbow. At 4 months, the follow-up remained uneventful. In selected instances, the off-label use of stent grafts may expand the therapeutic options of the vascular access team.

Timely thrombectomy can improve patency of hemodialysis arteriovenous fistulas

OBJECTIVE

The urgency with which salvage of thrombosed vascular accesses for dialysis should be attempted remains unknown. We examined the effect of a timely thrombectomy approach on vascular access outcomes for dialysis.

METHODS

A before-and-after study was conducted with patients on hemodialysis who had undergone endovascular thrombectomy. A timely thrombectomy initiative (ie, salvage within 24 hours of thrombosis diagnosis) was started in July 2015 at our institution. Data about thrombectomy procedures, performed within 1 year before and after the initiative was introduced, were abstracted from an electronic database. Immediate outcomes and patency outcomes were compared between the preinitiative (control) and postinitiative (intervention) groups.

RESULTS

During the study period, 329 patients were enrolled, including 165 cases before and 164 cases after the initiative. The intervention group had more thrombectomy procedures performed within 24 hours (93% vs 55%; P < .01) and within 48 hours (97% vs 79%; P < .01) than the control group. No between-group differences in procedural success or clinical success rates were found. At 3 months, the intervention group had a higher postintervention primary patency rate than the control group, although this did not reach statistical significance (58% vs 48%; P = .06). After stratification into native or graft accesses, the patency benefit was observed in the native access group (68% vs 50%; P = .03) but not in the graft access group (50% vs 46%; P = .65). After adjusting for potential confounders, timely thrombectomy remained an independent predictor of postintervention primary patency (hazard ratio, 0.449; 95% confidence interval, 0.224-0.900; P = .02) for native dialysis accesses.

CONCLUSIONS

Our results suggest that a timely thrombectomy approach, in which salvage is attempted within 24 hours of thrombosis diagnosis, improves postintervention primary patency of native but not graft accesses for dialysis.

Factors Affecting Patency following Successful Percutaneous Intervention for Dysfunctional Hemodialysis Vascular Access

BACKGROUND

This study aimed to investigate the patency following initial successful percutaneous transluminal angioplasty (PTA) for untreated dysfunctional hemodialysis vascular access and to identify predictors of PTA durability.

METHODS

This retrospective observational study included data of 132 consecutive initial PTA of hemodialysis vascular access in 126 patients who showed immediate technical and clinical success and had at least 1 year of follow-up data.

RESULTS

The mean duration of primary and secondary patency post-PTA was 16 and 27 months, respectively. On multivariate adjusted Cox regression analysis, dyslipidemia (P < 0.001), use of insulin (P = 0.016), and arteriovenous graft (AVG) (P = 0.016) were significantly associated with shorter primary patency. Dyslipidemia (P < 0.001), use of antiplatelet medication (P = 0.013), and failed vascular access (P = 0.004) were significant predictors of secondary patency loss. Use of statin was the only clinical variable associated with increased primary and secondary patency (P < 0.001). According to a subgroup analysis on the type of vascular access and dysfunction, primary and secondary patency rates were significantly higher in the arteriovenous fistula (AVF) and failing vascular access groups than AVG and failed vascular access groups, respectively. Early dysfunction (within 6 months) was significantly higher in the AVG and failed vascular access groups after initial PTA, but there was no significant difference after multiple PTAs.

CONCLUSIONS

Post-PTA primary and secondary patency rates were significantly higher with AVF and failing vascular access. The use of statin was associated with increased primary and secondary patency after initial successful PTA in this study.

Results of Stent Graft Placement to Treat Cephalic Arch Stenosis in Hemodialysis Patients with Dysfunctional Brachiocephalic Arteriovenous Fistulas

PURPOSE

To determine effectiveness of the VIABAHN (W.L. Gore & Associates, Flagstaff, Arizona) stent graft to treat cephalic arch stenosis in patients with dysfunctional brachiocephalic arteriovenous fistulas after inadequate venoplasty response.

MATERIALS AND METHODS

Between 2012 and 2015, patients with failed venoplasty of symptomatic cephalic arch stenosis received a VIABAHN stent graft. Follow-up venography was performed at approximately 3, 6, and 12 months. Data were retrospectively analyzed with patency estimated using Kaplan-Meier and log-rank methodology. There were 39 patients included.

RESULTS

Technical and clinical success was 100%. Primary target lesion patency was 85% (95% confidence interval [CI], 69%-93%), 67% (95% CI, 50%-80%), and 42% (95% CI, 25%-57%) at 3, 6, and 12 months. There was no significant difference in patency with regard to sex or age (P = .8 and P = .6, respectively). Primary assisted patency was 95% (95% CI, 82%-99%) at 3, 6, and 12 months. Access circuit primary patency was 85% (95% CI, 69%-93%), 67% (95% CI, 50%-80%), and 42% (95% CI, 25%-57%) at 3, 6, and 12 months. There was no significant difference in patency between patients with the stent graft as the first treatment episode in the cephalic arch and those that had previous intervention at this site (P = .98). There were 48 repeat venoplasty procedures performed in the cephalic arch to maintain patency, including 7 repeat VIABAHN insertions. No complications were encountered.

CONCLUSIONS

The VIABAHN stent graft is a safe, effective, and durable device for treating cephalic arch stenosis when venoplasty fails.

Benefits of Long Versus Short Thrombolysis Times for Acutely Thrombosed Hemodialysis Native Fistulas

INTRODUCTION

Local thrombolysis with a time of exposure to recombinant tissue plasminogen activator of 15 to 150 minutes is commonly used to declot acutely thrombosed hemodialysis fistulas. The duration of thrombolysis for the restoration of arteriovenous blood flow remains controversial. The aim of this study was to investigate the outcomes of long thrombolysis treatment (LTT, 3 hours or more) and short thrombolysis treatment (STT, less than 3 hours) in our institution.

METHODS

We retrospectively analyzed 86 interventional declotting procedures (28 STT and 58 LTT) applied to 86 acutely thrombosed hemodialysis fistulas. The intervention time (IT) following thrombolysis (from the initial fistulography to the end of the angioplasty maneuvers), the time of day of the intervention (ie, during working hours vs off-hours), and the need for temporary catheter placement (TCP) were assessed. Success was defined as complete access recanalization, and major adverse events were defined as ischemia, bleeding, and access rupture.

RESULTS

The ITs were reduced after LTT (63.3 [9.3] minutes) compared to STT (106.7 [24.7], P = .01), but there was no difference in success rate (85.7% STT, 89.7% LTT, P = .722). While all (100%, 58/58) of the angioplasty maneuvers after LTT were performed during regular working hours, 75% (21/28) of those following STT were managed during off-hours ( P < .001). Despite the longer treatment, the need for TCP was not increased after LTT (10.7%) compared to STT (12.1%, P = .515), and the major complication rate was reduced (3.4% after LTT and 28.6% after STT, P = .004).

CONCLUSION

Long thrombolysis treatment results in shorter and less complicated percutaneous stenosis treatments during regular working hours. Despite the LTT of up to 25 hours until access for dialysis was achieved, no increase in the risks of TCP or major adverse events were observed following LTT.

Paclitaxel-Coated Balloons for the Treatment of Symptomatic Central Venous Stenosis in Dialysis Access: Results from a Randomized Controlled Trial

PURPOSE

To compare the clinically-assessed intervention-free period (IFP) of paclitaxel-coated balloon (PCB) vs conventional balloon angioplasty (CBA) for the treatment of symptomatic central venous stenosis (CVS) in dialysis access.

MATERIALS AND METHODS

Within 20 months, 40 dialysis patients (19/40 arteriovenous fistulae [AVFs] and 21/40 arteriovenous grafts [AVGs]) were randomized to undergo angioplasty either with a PCB (PCB group, n = 20; 14/20 male; age: 56.7) or CBA (CBA group, n = 20; 15/20 male; age: 57). There were 15/20 restenotic lesions in PCB group and 12/20 in CBA group. In 25/40 cases, patients had an ipslateral catheter insertion in the past. Primary endpoint was clinically-assessed intervention-free period (IFP) of the treated segment at 6 months, while secondary endpoints included complication rates during follow-up period and identification of factors influencing IFP.

RESULTS

Median IFP was significantly better in PCB group (PCB group: 179 days, vs CBA group: 124.5 days, P = .026). Mean follow-up period was 180 days (range, 5-479). There was no significant difference between AVGs and AVFs (P = .17), treatment of de novo vs restenotic lesions (P = .33), or prior presence of catheter insertion (P = .21). No complications were observed. In restenotic lesions in PCB group, longitudinal comparison between treatments also showed a significant difference in favor of PCB treatment (median IFP in PCB* group 177 vs 91 days in CBA* group; P = .01).

CONCLUSIONS

In this prospective study, PCB had significantly better results compared with CBA for the treatment of symptomatic central venous stenosis in dialysis access. Retrospective longitudinal comparison of treatments in the same patients also showed a significant difference in favor of PCBs.

Percutaneous Endovascular Treatment to Salvage Non-Maturing Arteriovenous Fistulas in a Multiethnic Asian Population

Introduction: An arteriovenous fistula (AVF) is the preferred method for haemodialysis in patients with end-stage renal failure. Previous studies have shown value in attempting percutaneous transluminal angioplasty (PTA) to salvage AVFs that fail to mature, but they are relatively small in size and mainly reported in Western populations. We reviewed our data of PTA in non-maturing AVFs to establish whether this technique is translatable to our local multiethnic population. Materials and Methods: We retrospectively reviewed the medical records and procedural images of 105 patients who had PTA for non-maturing AVFs performed at our department from January 2008 to January 2011. Technical success was defined as ≤30% residual stenosis after angioplasty. Clinical success was defined as at least 1 successful haemodialysis session within 4 weeks after PTA. Results: All 105 patients underwent angioplasty for at least 1 haemodynamically significant stenosis. Six (5.7%) had additional embolisation of accessory veins. Technical success was achieved in 95.2% of cases. The clinical success rate was 76.2%. Primary patency rates at 3, 6 and 12 months were 83%, 45% and 28%, respectively. Secondary patency rates at 3, 6 and 12 months were 90%, 79% and 70%, respectively. The minor complication rate was 18.1%. No major complications were encountered. An average of 1.7 interventions per access-year was required to maintain AVF patency. Patients with a preoperative vein size >2.0 mm and age <55 years were more likely to achieve clinical success, although not statistically significant. Conclusion: PTA is a viable option to help salvage non-maturing AVFs in a multiethnic Asian population. Key words: Angioplasty, Chronic renal disease, Haemodialysis, Interventional radiology

Ultrasound-guided angioplasty for treatment of peripheral stenosis of arteriovenous fistula - a single-center experience

PURPOSE

In patients with end-stage renal disease, arteriovenous fistulas (AVFs) are the access of choice for hemodialysis but are often complicated by stenosis. We present single-center experience of 78 ultrasound-guided angioplasty procedures for treating peripheral stenoses of AVFs.

METHODS

Between January 2013 and November 2015, 78 angioplasties were performed under ultrasound guidance in 53 patients with end-stage renal disease who were referred from dialysis centers with low flow rate, difficult cannulation, increased cannulation site bleeding, immature or thrombosed AVF. Angioplasties were carried out in the presence of a structural lesion in the AVF resulting in at least 50% reduction in vein diameter with a blood flow of &lt;250 mL/min or a peak systolic velocity &gt;300 cm/s. Clinical success, anatomical success and post-intervention primary and secondary patency rates at 6, 12, 18 and 24 months were studied.

RESULTS

In 49/53 patients (92.4%), 74 angioplasty procedures were successfully performed, whereas 4/53 patients (7.6%) had primary failure. A total of 35/49 patients (71.4%) underwent single angioplasty procedure whereas 14/49 patients (28.6%) underwent multiple angioplasty procedures. Post-intervention primary patency rates at 6, 12, 18 and 24 months were 78.6%, 60.2%, 53.8% and 48.9%, respectively. Post-intervention secondary patency rates at 6, 12, 18 and 24 months were 100%, 100%, 95.4% and 89%, respectively. Clinical success and anatomical success was 94.8% and 89.7%, respectively.

CONCLUSIONS

Ultrasound-guided angioplasty is an effective method with good long-term outcomes in selected dialysis patients with peripheral stenosis of AVF.

Time-extended local rtPA infiltration for acutely thrombosed hemodialysis fistulas

INTRODUCTION

This study describes results of a modified local thrombolysis technique for acutely thrombosed hemodialysis (HD) arteriovenous fistulas (AVF), which is characterized by prolonged recombinant tissue plasminogen activator (rtPA) local exposure times. Contrary to the standard lyse- and- wait (L&W) technique with local reaction times of 20-40 minutes, the modified protocol allows timing of challenging angioplasty maneuvers to the next regular working day.

METHODS

From February 2009 to April 2014, 84 patients on HD presented with 152 acutely thrombosed AVF. They proceeded to local thrombolysis including a single shot infiltration of rtPA, local reaction time up to 40 hours and finally percutaneous stenosis angioplasty. Success rates, major adverse events and need for temporary catheter placements (TCP) were retrospectively analyzed.

FINDINGS

The local thrombolysis time after single shot infiltration was 18.6 ± 6.2 (range 2-40) hours. Mean rtPA- dosage was 2.7 mg ± 1.2. The overall success rate was 89.5% and the major complication rate was 3.3%, whereas TCP was necessary in 12.5%. The PP/SP at 1, 3, 6, 12, 18, and 24 month were 86% ± 3%/95% ± 2%, 68% ± 4%/92% ± 2%, 43% ± 4%/90% ± 2%, 28% ± 4%/82% ± 3%, 12% ± 3%/82% ± 3%, 7% ± 2%/63% ± 4%, respectively.

CONCLUSION

The modified L&W technique with prolonged local rtPA reaction times is a safe and effective declotting procedure. The need for TCP was not increased and therefore comparable to the standard technique.

Paclitaxel-Coated Balloons for the Treatment of Dysfunctional Dialysis Access. Results from a Single-Center, Retrospective Analysis

PURPOSE

To investigate the safety and effectiveness of lutonix paclitaxel-coated balloon (PCB) for the treatment of dysfunctional dialysis access.

MATERIALS AND METHODS

This was a single-center, single-arm, retrospective analysis of 39 patients (23 male, 59 %) undergoing 61 interventions using 69 PCBs in a 20-month period. There was a balance between arteriovenous fistulae (AVF) and grafts (AVG) (20 AVFs, 19AVGs), and the majority of lesions were restenotic (25/39, 64.1 %). Mean balloon diameter used was 6.6 mm and length 73.4 mm. Primary outcome measure was target lesion primary patency (TLPP) at 6 months, while secondary outcome measures included factors affecting TLPP and major complications. As there were lesions treated more than once with PCB, authors also compared patency results after first and second PCB angioplasty.

RESULTS

TLPP was 72.2 % at 6 months with a median patency of 260 days according to the Kaplan-Meier survival analysis. No major complications occurred. TLPP between AVFs and AVGs (311 vs. 237 days, respectively; p = 0.29) and de novo and restenotic lesions was similar (270.5 vs. 267.5 days, respectively; p = 0.50). In 14 cases, in which lesions were treated with two PCB angioplasties, a statistically significant difference in TLPP after the second treatment was noted (first intervention 179.5 days vs. second intervention 273.5 days; p = 0.032).

CONCLUSION

In this retrospective analysis, Lutonix PCB proved to be safe and effective in treating restenosis in dysfunctional dialysis access with results comparable to the literature available. Larger studies are needed to prove abovementioned results.

Transjugular Access for Endovascular Treatment of Immature Autogenous Arteriovenous Fistulae

PURPOSE

To assess the feasibility and outcome of transjugular access for endovascular treatment of immature arteriovenous fistulae (AVFs).

MATERIALS AND METHODS

Between August 2013 and January 2016, 90 patients (mean age, 64.5 y ± 12.8) underwent endovascular treatment of immature AVFs via transjugular access. The mean age of fistulae was 3.3 months ± 1.8. Total procedure time and technical and clinical success rates of endovascular procedures were assessed. Primary and secondary patency rates were calculated according to the Kaplan-Meier method, and complications were assessed.

RESULTS

All patients had inflow lesions, among which 19 (21.1%) had occlusions. The juxtaanastomotic segment was the most common site (44.3%). Transjugular access was successful in 83 patients (92.2%), and 7 required additional standard or transarterial access. The mean procedure time was 36.5 minutes. Technical and clinical success rates were 98.9% and 90.5%, respectively. Mean primary and secondary patency durations were 14.3 months ± 1.7 and 31.0 months ± 0.7, respectively. Primary patency rates at 3, 6, and 12 months were 84.4%, 67.3%, and 48.8%, respectively. Secondary patency rates at 6 and 18 months were 98.6% and 95.5%, respectively. Venous rupture occurred as a result of balloon inflation in 9 patients (10%), and was managed by balloon tamponade. There were no complications related to transjugular access during a mean follow-up period of 12.6 months.

CONCLUSIONS

Transjugular access for angioplasty of immature AVFs is feasible and safe. Potential problems associated with access in the outflow vein could be avoided by transjugular access.

Comparison of Open-Cell Stent and Closed-Cell Stent for Treatment of Central Vein Stenosis or Occlusion in Hemodialysis Patients

Background

Central vein stenosis or occlusion is a common complication that can lead to significant morbidity and dysfunction of access in the hemodialysis patient. More lesions can develop over time, and preserving access becomes a challenge as life expectancy of the hemodialysis patient increases.

Objectives

The goal was to compare long-term results and determine the outcomes of open-cell stent versus closed-cell stent for central vein stenosis or occlusion in hemodialysis patients.

Patients and Methods

From 1997 to 2015, in 401 hemodialysis patients, stent placement for central vein stenosis or occlusion was performed if balloon angioplasty was unsatisfactory, due to elastic recoil or occurrence of restenosis within 3 months. When thrombus was present, primary stenting was performed. A total of 257 open-cell stents and 144 closed-cell stents were used. Angiographic findings including lesion site, central vein stenosis or occlusion, and presence of thrombosis and complication were evaluated. Primary patency rate and mean patency rate of the stent were compared between two stent groups by Kaplan-Meier survival analysis.

Results

For the open-cell stent group, 159 patients were diagnosed as central vein stenosis and 98 were occlusion. For the closed-cell stent group, 78 were stenosis and 66 were occlusion. There were two complications for central migration and two for procedure-related vein rupture. Open-cell stents and closed-cell stents had mean patency rates of 10.9 ± 0.80 months and 8.5 ± 10.87 months, respectively (P = 0.002).

Conclusion

The open-cell stent is effective and its performance is higher than that obtained with the closed-cell stent for treating central vein stenosis or occlusion in hemodialysis patients.

Endovascular Stent Graft Repair is an Effective and Safe Alternative Therapy for Arteriovenous Graft Pseudoaneurysms

OBJECTIVE/BACKGROUND

Pseudoaneurysm formation occurs in 2-10% of hemodialysis arteriovenous grafts (AVGs). Surgical repair often requires pseudoaneurysm resection, interposition graft placement, and insertion of a catheter as a bridge. Endovascular stent graft repair is a controversial alternative therapy. This study was performed to examine the effectiveness and mid-term outcomes of stent graft repair for AVG pseudoaneurysms.

METHODS

All patients who had undergone stent graft repair for AVG pseudoaneurysms between December 2012 and July 2015 were identified from hospital medical records for retrospective analysis. Outcome measures were technical success, early and late complications, and primary and secondary patency rates.

RESULTS

A total of 37 stent graft repairs of AVG pseudoaneurysms were performed in 35 patients (42.9% men; mean age 66.9 years). The mean time from AVG creation to pseudoaneurysm repair was 69 months. The indications of treatment (as per the institutional policy) were large pseudoaneurysm (56.7%), impending rupture (27.1%), and bleeding (16.2%). Mean pseudoaneurysm diameter was 23.0 mm. The most common diameter and length of stent graft used were 7 mm (67.6%) and 50 mm (48.6%), respectively. Technical success was 100%. Only one early complication occurred after stent graft repair, which was due to recurrence of the pseudoaneurysm as a result of a short landing zone. Late complications included infection (17.1%) and thrombosis (37.1%). The 1, 6, and 12 month primary patency rates were 89.2%, 55.5%, and 22.0%, respectively. The 1, 6, and 12 month secondary patency rates were 100%, 88.6%, and 78.6%, respectively. The median follow up was 12.3 months.

CONCLUSIONS

The study demonstrates that endovascular stent graft repair is an effective and safe alternative therapy for AVG pseudoaneurysms. However, the rate of thrombosis and infection was high and needs to be balanced against open surgery in future studies.

Initial clinical use of a novel mechanical thrombectomy device, XCOILTM, in hemodialysis graft and fistula declot procedures

PURPOSE

We aimed to evaluate the safety and effectiveness of a novel catheter-based mechanical thrombectomy device, XCOILTM, as a first line therapy to restore patency of thrombosed dialysis grafts and fistulae.

METHODS

In 2010, 18 consecutive/sequential patients (11 male, 7 female; median age, 52 years; age range, 32-69 years) with occluded arteriovenous grafts (n=15) or fistulae (n=3) were treated with XCOILTM (NexGen Medical Systems Inc.) without adjunctive thrombolytic drugs. XCOILTM was advanced distal to the thrombus within the outflow vein as well as distal to the arterial inflow platelet thrombin plug, using a 4F angiographic catheter. The percentage of thrombus cleared, primary patency, procedure time, and XCOILTM performance were documented.

RESULTS

Thrombosis occurred 1-30 days prior to the procedure. Thrombosed segments of graft/fistula measured 10-50 cm. Pre- and postprocedure angiography demonstrated that in 15 of 18 cases (83%) XCOILTM removed 80%-100% of the venous outflow thrombus. In 11 of 14 cases (79%), the platelet thrombin plug was also removed. Thrombectomy procedure time averaged 8 min, with one to three passes with the XCOILTM required. No evidence of distal embolization or graft/vessel injury was found on angiography following clot removal. In four cases in whom patency was not restored with XCOILTM, subsequent use of other clot removal devices also failed to restore patency. In one case with severe venous stenosis, the device failed to deploy and the thrombus was not captured. No intraprocedural complications related to XCOILTM use occurred.

CONCLUSION

XCOILTM is an effective and safe first-line therapy option for the treatment of thrombosed hemodialysis grafts/fistulae. Rapid removal of intact thrombus and platelet thrombin plug can be achieved without adjunctive thrombolytics.

Predicting Factors for Successful Maturation of Autogenous Haemodialysis Fistulas After Salvage Percutaneous Transluminal Angioplasty in Diabetic Nephropathy: A Study on Follow-Up Doppler Ultrasonography

BACKGROUND

Maturation failure of autogenous arteriovenous fistula (aAVF) has been increasing after surgical procedures and the salvage percutaneous transluminal angioplasty (sPTA) for immature aAVF has been identified as an effective treatment modality.

OBJECTIVES

The aim of this study was to identify factors predicting successful aAVF maturation and to determine positive technical aspects of sPTA.

PATIENTS AND METHODS

We retrospectively reviewed medical records and radiological images of 59 patients who had undergone sPTA for non-maturing aAVFs. We analysed images from pre-surgical mapping Doppler ultrasonography, angiography, and angioplasty and follow-up Doppler ultrasonography performed within two weeks after sPTA. We assessed the following factors, for their ability to predict successful aAVF maturation: 1) patient factors (age; sex; co-morbidities; and aAVF age, side and type); 2) vessel factors (cephalic vein diameter and depth, presence of accessory veins, and pre- and postoperative radial artery disease); 3) lesion factors (stenosis number, location and severity); and 4) technical factors (presence of residual stenosis and anatomic success ratio (ASR) on follow-up Doppler ultrasonography).

RESULTS

The technical and clinical success rates were both 94.9% (56/59); the mean ASR was 0.84. An ASR of ≥ 0.7 and no significant residual stenosis (< 30%) (both P < 0.001) on two-week follow-up Doppler ultrasonography predicted successful aAVF maturation.

CONCLUSION

For more precise prediction of successful aAVF maturation after sPTA, short-term follow-up Doppler ultrasonography (< 2 weeks) was useful. If the ASR was < 0.7 or if residual stenosis was ≥ 30%, immediate repeat sPTA is recommended.

Endovascular Stent Placement for Hemodialysis Arteriovenous Access Stenosis

This study aims to report the outcomes of nitinol and polytetrafluoroethylene covered stent placement to treat hemodialysis arteriovenous access stenosis at a single center over a five-year period. Clinical and radiological information was reviewed retrospectively. Poststent primary and secondary patency rates were determined using Kaplan-Meier analysis. Ten clinical variables were subjected to multivariate Cox regression analysis to determine predictors of patency after stent placement. During the study period 60 stents were deployed in 45 patients, with a mean follow-up of 24.5 months. The clinical and anatomical success rate was 98.3% (59/60). Poststent primary patency rates at 6, 12, and 24 months were 64%, 46%, and 35%, respectively. Poststent secondary patency rates at 6, 12, and 24 months were 95%, 89%, and 85%, respectively. Stent placement for upper arm lesions and in access less than 12 months of age was associated with reduced primary patency (adjusted hazards ratio [HR] 5.1, p = 0.0084, and HR 3.5, p = 0.0029, resp.). Resistant or recurrent stenosis can be successfully treated by endovascular stent placement with durable long-term patency, although multiple procedures are often required. Stent placement for upper arm lesions and in arteriovenous access less than 12 months of age was associated with increased risk of patency loss.

The MILLER banding procedure as a treatment alternative for dialysis access steal syndrome: a single institutional experience

OBJECTIVE

To describe a single institutional experience with minimally invasive limited ligation endoluminal-assisted revision (MILLER) for treatment of dialysis access steal syndrome (DASS).

MATERIALS AND METHODS

Twenty patients were retrospectively identified that underwent 30 MILLER band procedures for DASS at our institution from March 2010 to December 2014. Technical success was defined by successful creation of MILLER band with preservation of flow for hemodialysis. Clinical success was defined as complete resolution of signs and symptoms with preservation of dialysis access in a 1-month postprocedural period. Primary MILLER band patency, postintervention-assisted primary access patency, and postprocedure secondary access patency are reported.

RESULTS

Technical success was achieved in all patients. Clinical success was achieved in 75% of patients after one banding procedure and in 95% of patients after two banding procedures. One patient experienced access thrombosis following the initial banding procedure which was subsequently treated and did not lead to loss of access. MILLER band patency was 83% at 1 month and 77% at 6 months. Postintervention-assisted primary patency was 95%, 93%, and 92% at 3 months, 6 months, and 1 year, respectively. Postintervention secondary patency was 86%, 68%, and 59% at 3 months, 6 months, and 1 year, respectively.

CONCLUSIONS

MILLER banding offers a less-invasive alternative to surgical therapy that appears to be safe and permits preservation of dialysis access.

Postintervention Patency Rates and Predictors of Patency after Percutaneous Interventions on Intragraft Stenoses within Failing Prosthetic Arteriovenous Grafts

PURPOSE

To determine postintervention patency rates after endovascular interventions on intragraft stenosis within failing prosthetic arteriovenous (AV) grafts, as well as predictors of patency.

MATERIALS AND METHODS

Retrospective review of percutaneous interventions on prosthetic AV grafts presenting with first-time intragraft stenoses over a 7-year period revealed 183 patients (81 male; mean age, 59.7 y). "Intragraft" was defined as 2 cm or more from the arterial or venous anastomosis. Procedural imaging was retrospectively reviewed. Patency rates were estimated by Kaplan-Meier test. Predictors of patency were calculated by Cox proportional-hazards model.

RESULTS

Two-hundred twenty-nine intragraft stenoses were identified in 183 grafts. Intragraft stenoses were treated at a median of 20.7 months (interquartile range, 12.0-33.9 mo) after graft creation. Graft thrombosis was present in 62%. The anatomic success rate of angioplasty was 85%. Fifteen percent required stent or stent-graft deployment because of inadequate response to angioplasty. A concurrent nonintragraft stenosis within the access circuit was identified in 76% of grafts. At 3, 6, and 12 months, postintervention primary patency rates were 56%, 40%, and 23%, respectively. Secondary patency rates were 84%, 77%, and 67%, respectively. The lesion-specific patency rates were 89, 75%, and 63%, respectively. Graft thrombosis (hazard ratio [HR], 1.43; P = .048) and concurrent nonintragraft lesion (HR, 1.51; P = .047) were independent negative predictors of primary patency. Graft thrombosis (HR, 1.81; P = .029) was a negative predictor of lesion patency, and stent or stent-graft deployment (HR, 0.42; P = .045) was a positive predictor of lesion patency.

CONCLUSIONS

Endovascular interventions on intragraft stenoses resulted in primary, secondary, and lesion-specific patency rates of 40%, 77%, and 75%, respectively, at 6 months. Stent or stent-graft deployment may prolong lesion patency.

Partial Aneurysmectomy of Venous Aneurysms in Arteriovenous Dialysis Fistulas

Upper extremity native arteriovenous fistulas (AVFs) continue to be the standard of care for hemodialysis patient’s access. Although autogenous fistulas are superior to catheters and synthetic grafts, they are not without their own complications. One complication is venous aneurysms that can lead to skin erosion, bleeding, and site loss. Although traditionally repaired with ligation, interposition grafts, or stent placement, in this article, we discuss our experience with aneurysmorrhaphy utilizing a thoracoabdominal (TA) stapler. Thirteen aneurysms were treated with the TA stapler at a single, nonuniversity hospital for all patients from 2012 to 2014. The average aneurysm diameter was 3.6 cm, and the average fistula age was 57.9 months. There were no bleeding complications or recurrences. The primary patency was 80% at 6 months, with a primary assisted patency of 90% during the same time frame. Aneurysmorrhaphy with the TA stapler appears to be a safe and viable option for the treatment of venous aneurysms associated with AVFs.

Paclitaxel-coated versus plain balloon angioplasty for dysfunctional arteriovenous fistulae: one-year results of a prospective randomized controlled trial

PURPOSE

To report 1-year results of a single-center randomized controlled trial comparing paclitaxel-coated balloon (PCB) versus high-pressure plain balloon angioplasty for the treatment of failing arteriovenous fistulae (AVFs).

MATERIALS AND METHODS

Forty patients (26 men; mean age, 61 y ± 14.63) were randomized at 1:1 to undergo PCB (n = 20) or high-pressure balloon (HPB; n = 20) angioplasty of dysfunctional AVFs. There were no significant differences in baseline demographics between groups. Enrollment required a clinical diagnosis of a dysfunctional AVF attributed to a single stenotic lesion verified with digital subtraction angiography. Primary endpoints included device success, anatomic success, clinical success, and target lesion revascularization (TLR)-free survival. Secondary endpoints included dialysis circuit primary patency and procedure-related complication rates.

RESULTS

Device success rates were 100% in the HPB group and 35% in the PCB group (P < 0001): further dilation with an HPB was needed to achieve anatomic success in 13 of 20 cases in the PCB group (65%). Anatomic and clinical success rates were 100% in both groups. TLR-free survival (PCB, 308 d; HPB, 161 d; hazard ratio [HR], 0.478; 95% confidence interval [CI], 0.236-0.966; P = .03) and access circuit primary patency (PCB, 270 d; HPB, 161 d; HR, 0.479; 95% CI, 0.237-0.968; P = .04) were significantly in favor of PCB angioplasty. No minor or major procedure-related complications occurred.

CONCLUSIONS

In this single-center study, the use of PCBs resulted in superior TLR-free survival and dialysis access circuit primary patency of dysfunctional AVFs. However, additional HPB postdilation was required in the majority of cases.

Endovascular recanalization of a thrombosed native arteriovenous fistula complicated with an aneurysm: technical aspects and outcomes

OBJECTIVE

To evaluate the technical aspects and outcomes of endovascular recanalization of a thrombosed native arteriovenous fistula (AVF) complicated with an aneurysm.

MATERIALS AND METHODS

Sixteen patients who had a thrombosed AVF complicated with an aneurysm (two radiocephalic and 14 brachiocephalic) were included in this study. Recanalization procedures were performed by mechanical thrombectomy using the Arrow-Trerotola percutaneous thrombectomy device and adjunctive treatments. We evaluated dose of thrombolytic agent, underlying stenosis, procedure time, technical and clinical success, and complications. The primary and secondary patency rates were calculated using the Kaplan-Meier analysis.

RESULTS

The thrombolytic agents used were 100000 U urokinase mixed with 500 IU heparin (n = 10) or a double dose of the mixture (n = 6). The thrombi in aneurysms were removed in all but two patients with non-flow limiting residual thrombi. One recanalization failure occurred due to a device failure. Aspiration thrombectomy was performed in 87.5% of cases (n = 14). Underlying stenoses were found in the outflow draining vein (n = 16), arteriovenous anastomosis or juxtaanastomosis area (n = 5), and the central vein (n = 3). Balloon angioplasty was performed for all stenoses in 15 patients. Two patients with a symptomatic central vein stenosis underwent insertion of a stent after balloon angioplasty. Mean procedure time was 116.3 minutes. Minor extravasation (n = 1) was resolved by manual compression. Both technical and clinical success rates were 93.8% (n = 15). The primary patency rates at 3, 6, and 12 months were 70.5%, 54.8%, and 31.3%, respectively. The secondary patency rates at 3, 6, and 12 months were 70.5%, 70.5%, and 47.0%, respectively.

CONCLUSION

Thrombosed AVF complicated with an aneurysm can be successfully recanalized, and secondary patency can be prolonged with endovascular treatment.

Percutaneous transluminal angioplasty for dysfunctional femoral hemodialysis graft

PURPOSE

We aimed to evaluate the safety and effectiveness of percutaneous transluminal angioplasty (PTA) for dysfunctional femoral arteriovenous graft and analyze clinical or anatomic predictors of graft patency.

METHODS

The records of 45 patients who underwent PTA or thromboaspiration for dysfunctional or thrombosed femoral arteriovenous graft from 2005 to 2012 were reviewed retrospectively. Primary and secondary patency rates were determined at three, six, and 12 months after PTA. The primary patency rate was analyzed according to the presence of diabetes mellitus, graft age from the time of creation to the first intervention (<12 months or ≥12 months), presence of thrombus, shape of graft (U-shape vs. straight-shape), anastomosis type of graft (femoral-femoral vs. femoral-saphenous), location of stenosis (central vs. peripheral), length of stenosis (<2 cm vs. ≥2 cm), degree of stenosis severity (<70% vs. ≥70%), and stent insertion.

RESULTS

A total of 124 PTAs were performed in 45 patients. The primary patency rate at three, six, and 12 months was 84.8%, 63.6%, and 24.2%, respectively. The secondary patency rate at three, six, and 12 months was 95.2%, 95.2%, and 85.7%, respectively. The mean duration of primary and secondary patency was 13.2 and 35.7 months, respectively. No significant clinical or anatomical predictors of primary patency could be identified. Stent placement had a negative effect on primary patency.

CONCLUSION

PTA is a safe and effective treatment for dysfunctional femoral arteriovenous grafts. Stent placement seems to improve technical success, but does not enhance the primary patency rate of dysfunctional femoral arteriovenous grafts.

Clinical outcome of percutaneous thrombectomy of dialysis access thrombosis by an interventional nephrologist

Background

Traditionally, the treatment of a thrombosed dialysis access in hemodialysis patients in Korea has been primarily performed by vascular surgeons and interventional radiologists. The objective of this study was to evaluate the outcome of percutaneous thrombectomy procedures performed by an interventional nephrologist.

Methods

From October 2010 to May 2014, 75 consecutive percutaneous thrombectomies were performed on 42 patients treated with maintenance hemodialysis. All percutaneous thrombectomy procedures were performed by an interventional nephrologist in a single hospital in Jeju, Korea. The thrombosed arteriovenous graft and arteriovenous fistula were declotted by thromboaspiration mechanical thrombectomy or pharmacomechanical thrombolysis. Kaplan–Meier survival analysis was performed to analyze the primary and secondary patency after the initial successful thrombectomy. Success and complication rates were identified and compared with the recommendations of the Kidney Disease Dialysis Outcomes Quality Initiative (KDOQI) guideline.

Results

The overall clinical success rate was 89.3% (67/75). In the successful cases, the postintervention primary (unassisted) patency rates at 30 days, 90 days, and 180 days were 79.9%, 56.6%, and 25.6%, respectively. The secondary patency rates at 30 days, 90 days, and 180 days were 92.2%, 85.7%, and 83.7%, respectively. There were no major complications, and all complications were treated successfully during the procedure.

Conclusion

The clinical success rate and primary patency rate at 3 months exceeded the recommendations of the KDOQI guideline, and were comparable to that of other reports. Percutaneous thrombectomy by an interventional nephrologist was safe and effective.

Outcomes of percutaneous interventions in transposed hemodialysis fistulas compared with nontransposed fistulas and grafts

PURPOSE

To compare postpercutaneous intervention outcomes of autogenous venous-transposition arteriovenous fistulas (AVFs) versus those of autogenous nontransposed AVFs (nAVFs) and prosthetic arteriovenous grafts (AVGs).

MATERIALS AND METHODS

A total of 591 hemodialysis accesses (195 transposed AVFs [tAVFs], 205 nAVFs, 191 AVGs) in 522 patients (278 male; mean age, 57 y; range, 15–91 y) underwent percutaneous transluminal angioplasty (PTA) and/or mechanical thrombectomy (ie, declotting). Access characteristics, surgical history, percutaneous interventions, postinterventional primary and secondary access patency, and follow-up data were collected. Cox proportional-hazards regression analyses, Fisher exact tests, and χ2 tests were performed.

RESULTS

Mean follow-up period was 32 months. Mean access ages at initial percutaneous intervention were 260 days (tAVF), 206 days (nAVF), and 176 days (AVG; P < .01). One-year postinterventional primary patency (PIPP) rates were 25% (tAVF), 24% (nAVF), and 14% (AVG). One-year postinterventional secondary patency (PISP) rates were 77% (tAVF), 61% (nAVF), and 63% (AVG). Median PIPP durations were 138 days (tAVF), 121 days (nAVF), and 79 days (AVG; P = .0001). Median PISP durations were 1,076 days (tAVF), 783 days (nAVF), and 750 days (AVG; P = .019). Total interventions needed to maintain PISP were 2.4 (tAVF), 1.3 (nAVF), and 3.2 (AVG) per patient-year (P < .001), which included 1.9, 1.2, and 1.4 PTAs (P < .01) and 0.45, 0.15, and 1.8 declotting procedures, respectively (P < .001).

CONCLUSIONS

Based on the number of percutaneous interventions needed to maintain PISP, these results confirm the current Dialysis Outcomes Quality Initiative access preference of nAVFs before tAVFs before AVGs. tAVFs offered superior postinterventional outcomes than AVGs. With additional interventions, tAVFs could even outperform nAVFs in terms of PISP.

Fistula first, graft on arterialized vein second

OBJECTIVES

Arterovenous grafts (AVGs) present a feasible solution for creating a vascular access in patients who are unsuitable for autogenous fistula (AVF). The aim of this study is to assess the prevention rate of vein stenosis, placing a graft on an arterialized vein (GAV) instead of an anastomized AVG in a native vein (GNV).

METHODS

This was a cohort study conducted from January 2009 to November 2012. All consecutive patients who underwent AVG in our institution were included. All patients requiring a secondary intervention were also referred to our centre. Patients underwent ultrasound follow up at first and the every month. A Kaplan-Meier method was used; a Log-rank test was used to identify whether significant difference existed between GAV and GNV (p < 0.05).

RESULTS

Forty-six grafts were placed. Twenty patients had arterialized receiving veins (group A), while 26 patients received an AVG immediately because they lacked autogenous veins suitable for fistula (group B).The average follow-up period was 16.1 months (range 0-41). The group A 41 months-patency rate was 84.3%, while group B was 43.7% (p = 0.06). Secondary patency was similar in the two groups.

CONCLUSIONS

Vein arterialization seems to prevent venous stenosis improving AVG-patency rate. More data are needed; however, the borderline p value encourages new studies.

Invasive radiologic management of hemodialysis fistulas: measuring flow with an endovascular catheter

OBJECTIVES

To analyze the values of flow obtained with an endovascular catheter, and to determine whether they are more reliable than angiographic and clinical findings for planning and for determining the outcome of invasive radiologic treatment of hemodialysis fistulas, as well as to determine the safety of this technique during interventional radiology procedures.

MATERIAL AND METHODS

We used endovascular catheters to measure flow in 341 vascular accesses for hemodialysis (162 [47.6%] distal fistulas, 132 [38.4%] humeral fistulas, and 47 [14%] arteriovenous grafts) in 598 procedures (a total of 3,051 flow measurements). Dysfunction was most commonly due to high pressures and flow deficits.

RESULTS

The catheter was used to measure the results of radiologic treatment in 419 (70%) cases and only to measure the control of flow in the hemodialysis access in 179 (30%) cases. In the cases where lesions of the access had been treated radiologically, the flow improved by a mean of 1,232ml/min. In 2 (0.35%) cases, the tip of the catheter perforated the wall of the vein; this complication was resolved by inflating a low pressure balloon.

CONCLUSIONS

Endovascular catheters are useful for measuring flow in invasive vascular radiology procedures for hemodialysis. In assessing the hemodynamic status of a vascular access, they are most helpful in determining whether stenosis is present.

Angioplasty of communicating veins to the brachial vein in haemodialysis patients with obliterated superficial veins of the upper arm

AIM

To evaluate the outcomes of angioplasty of the communicating veins when superficial veins of the upper arm were almost totally obliterated in haemodialysis patients.

MATERIALS AND METHODS

Twenty-one angioplasties of the communicating veins that were performed for failing haemodialysis fistulas in patients with almost totally obliterated superficial veins of the upper arm from December 2006 to March 2011 were retrospectively reviewed. Fistulas were of the following types: native radiocephalic fistulas (n = 20) and radio-antecubital fistulas (n = 1). All angioplasties were performed using 5-8 mm conventional balloons. Cutting balloon angioplasty was additionally performed in five patients. The primary, secondary, and target lesion patency rate was calculated using Kaplan-Meier analysis.

RESULTS

The communicating vein was located in the antecubital fossa. Technical and clinical success rates were 100% and 95.2%, respectively. Follow-up duration was 1-52 months (mean 20 months). The primary patency rates were 76%, 43%, and 29% at 3, 6, and 12 months, respectively, and target lesion patency rates were 81%, 62%, and 43% at 3, 6, and 12 months, respectively. The secondary patency rates were 81%, 76%, and 57% at 3, 6, and 12 months, respectively. There were no major or minor complications.

CONCLUSION

Angioplasty of the communicating vein is effective in restoring function in failing haemodialysis fistula in patients with obliterated superficial veins of the upper arm.

Predictors of patency after balloon angioplasty in hemodialysis fistulas: a systematic review

Percutaneous transluminal angioplasty (PTA) is an established treatment for dysfunctional hemodialysis fistulas. This article systematically reviews evidence for predictors of patency after PTA. Outcomes assessed were primary, assisted primary, and secondary patency after intervention, and findings were summarized descriptively. This review included 11 nonrandomized observational studies of 965 fistulas in 939 patients. Follow-up ranged from 0 days to 10 years. Study quality was overall suboptimal. Newer fistulas and longer lesion length may be associated with primary patency loss after PTA. Further studies are needed to confirm these findings, to identify potentially modifiable factors, and to guide the testing of new endovascular devices.

Incidence of arterial micro-embolization during percutaneous AngioJet thrombectomy of hemodialysis grafts

PURPOSE

This study was designed to investigate the incidence of arterial embolization using a peripheral protection filter device in a series of patients undergoing percutaneous mechanical thrombectomy for the management of thrombosed hemodialysis arteriovenous grafts (AVGs).

METHODS

This prospective, single-center study included all eligible patients presenting during an 18-month period to undergo AVG percutaneous thrombectomy. Inclusion criteria was a recently thrombosed AVG with 2 cm of artery before the next arterial branching. Primary endpoint was the incidence of distal arterial macro- and micro-embolization determined by both digital subtraction angiography and histopathological analysis of the material collected. Secondary endpoints included quantitative measurements of the specimens using a 0+ (no material) to 3+ (maximum load) score.

RESULTS

In total, 42 patients met the study's inclusion criteria. No procedure-related complications or angiographically evident arterial embolization were noted. Macroscopically evident material was present in 47.6% (20/42 filters). Histopathology demonstrated that the embolic material was primary consisted of fibrin conglomerates and platelets (median score: 1.5, confidence interval: 1.0-3.0), whereas inflammatory cells, trapped erythrocytes, extracellular matrix, cholesterol clefts, foam cells, necrotic core, and smooth muscle cells also were detected. Mean total area of embolic material was 5.04 mm(2) (range 0.05-5.21). The mean major axis of the largest particle was 1.83 mm (range 0.29-6.64), whereas 19% (8/42) contained particles with major axis >1 mm and 12% (5/42) with major axis >3 mm.

CONCLUSIONS

In this study, the percentage of arterial micro-embolization was significantly higher than previously reported. However, the detrimental, long-term, clinical relevance remains to be determined.

Percutaneous transluminal angioplasty of a non-mainstream venous route to restore an occluded hemodialysis fistula

PURPOSE

To report the usefulness of percutaneous transluminal angioplasty (PTA) of a non-mainstream venous route in an occluded native hemodialysis fistula when a mainstream outflow vein could not be traversed.

MATERIALS AND METHODS

This cohort included seven patients with an occulted hemodialysis fistula with difficulty in traversing via a mainstream route. A non-mainstream vein near the occluded portion was traversed until it connected with a proximal large-sized vein and the route was dilated using a 4- or 5-mm balloon catheter. Metallic stent placement was performed, if necessary. Technical aspects and long-term patency was evaluated.

RESULTS

PTA could be performed in all patients; however, stent placement was required in two because of residual stenosis and clotting. The clinical success rate of fistula restoration was 100 %. Fistula dysfunction recurred in six patients 17-668 days (mean ± standard deviation 229.3 ± 225.0) later. PTA was repeated in four patients, but not in two. The mean duration of the primary patency was 336.6 ± 417.2 days (range 17-1,190) and that of the secondary patency was 897.1 ± 801.4 days (range 17-2,230).

CONCLUSION

PTA of a non-mainstream venous route is useful for restoring an occluded hemodialysis fistula when the mainstream outflow vein cannot be traversed.

Effect of the time to intervention on the outcome of thrombosed dialysis access grafts managed percutaneously

PURPOSE

We aimed to investigate the effect of the time interval from the clinical presentation of a thrombosed dialysis access graft to intervention on procedure success.

MATERIALS AND METHODS

Records from two academic institutions for patients who underwent percutaneous thrombectomy of occluded surgical hemodialysis graft access sites in interventional radiology from 2006 to 2011 were reviewed retrospectively. The following data were recorded: gender, age, time and date of the initial request for a thrombectomy and the procedure, age of the surgical access, angiographic outcome, and clinical outcome (successful or unsuccessful postinterventional dialysis). Univariate and multivariate logistic regression were used to evaluate whether the time to intervention significantly affected the study endpoint.

RESULTS

In total, 268 percutaneous thrombectomies were performed in 139 patients. Of these 224 (83.5%) were categorized as successful and 44 (16.4%) as unsuccessful. The time to intervention was 19.9±30.1 vs. 22±35 hours for successful and unsuccessful procedures, respectively. The difference between the two was not significant, and there were also no significant differences in covariate distributions between successful and unsuccessful outcomes.

CONCLUSION

During the first 72 hours following clinical presentation of a thrombosed dialysis access graft, time to intervention may be considered independent of procedure outcome.

Percutaneous interventions in failing "necklace" hemodialysis grafts: long-term outcomes

PURPOSE

To determine primary and secondary patency after percutaneous interventions for malfunctioning anterior chest wall ("necklace") arteriovenous grafts (AVGs) for hemodialysis.

MATERIALS AND METHODS

Records of six consecutive patients with subclavian artery-to-contralateral subclavian vein necklace AVGs were reviewed. Patients underwent 34 procedures, including 28 balloon angioplasties, 24 pharmacomechanical thrombolyses, and six stent placements. Patency intervals after graft placement and after first intervention were calculated.

RESULTS

After 3 months, primary and secondary patency rates were 33% (two of six grafts) and 67% (four of six grafts), respectively. At 12 months, primary and secondary patency rates were 17% (one of six grafts) and 50% (three of six grafts), respectively. Median and mean primary patency times were 49 and 374 days, and median and mean secondary patency times were 293 and 575 days, respectively. The anatomic success rate of percutaneous interventions in malfunctioning AVGs was 97% (33 of 34 cases). At 3 years after implantation, the graft patency rate was 57% (four of seven grafts).

CONCLUSIONS

Percutaneous interventions were effective at maintaining patency in failing necklace AVGs. However, their primary and secondary patency were inferior to those cited in extremity AVG guidelines set forth by the Society of Interventional Radiology.